I give up

Head gasket is good :)
The autochoke is definitely funtional it is.moving the flap wide open once warm.
Coil remains cool and I believe I've still got a strong spark :)... keep chucking fresh plugs in. Whilst I clean others up.
A hotter fuel mixture is easier to ignite? But an overly rich formula isn't
My thinking is that it can cope whilst been continually revved as it burns off fuel... if left it slowly builds up and eventually becomes too wet to ignite.
I can tell thar by the misfiring sound of unburnt fuel getting more frequent the longer its left ... if I idle it at 1500/2000rpm it'll sit there quite happy all day... but STILL bog down under hard throttle
 
Hmm need special flat screwdriver with forked tongue... like a chip fork but metal
1378568013905.jpg
 
Should of pressed send on my last post eh

Temp built up... starts misfiring and dies again as before. Mixture screw hasn't changed a thing
 
Didn't think to check. Nor did I clean em before I altered it... will take one out

Got another video coming up too
 
@enuo
One test I did do... it bogs down on hard throttle and we assume overfueling

With that in mind I thought it may need more air. So I opened the second bore manually at the same rate. It didn't bog down it simply died straight away

So it seems that its overfueling then going lean on hard throttle :/

Next thing I can try is the accelerator pump .. it was slightly weaker than I thought... so I'm gonna pursue that line of though next though that requires the top of the carb off... so I've gotta let it cool... adjust... start run up to temp.. and see results...
It does this on cold also and that is the only thing unchanged not temp related
 
It'll run slightly rich when cold anyway, and the mixture leans as the autochoke kicks in. I said before it sounded like it was running lean, try fitting the air filter see if it improves, that will richen the mixture up slightly no? Or try slowly richening the mixture and see if blipping gets any improvement...
 
Its the same with air filter on :(
I'm with you on lean... but the plugs are still black?... will clean em up and try again in a mo.
I've leaned the mixture out myself and it made no difference.... so I'll screw it back in for a richer mixture
 
Haven't tested it yet.. unexpected visitor... requiring his arches grinding.... its saturday !!!!
And while he was here his bottom rad pipe popped off... I kindly fitted it again
Easiest £40 ever??
 
@enuo this was probably mentioned but.... these jets... I have 6...
2x accelerator jets
2x main jets
2x idle jets

I cleaned the first 2 pairs... but I dont think I cleaned my idle ones... reckon that could be it
 
h701micra said:
@enuo this was probably mentioned but.... these jets... I have 6...
2x accelerator jets
2x main jets
2x idle jets

I cleaned the first 2 pairs... but I dont think I cleaned my idle ones... reckon that could be it
Click to expand...
Could be, I'm unfarmiliar with downdraught carbs though sorry, can only help with the very basics
 
Found something interesting... accelerator pump solenoid... well I've never had it connected but I still have the old loom kicking about. Maybe time to plug it in? As it attaches to a coolant sensor and a air temp sensor
 
Doesn't an anti dieseling valve just dump a load of air into the engine to make the mixture too cold/lean to compression ignite?
 
i think your type opens an air valve andy, that makes it mad lean when you turn the key off.
some types of a/d/v shut the fuel off mechanically eh
 
When I took mine off my spitfire, all it did was cause run on on low octane fuel so would have to stall engine with the gearbox... I suppose if it s stuck open it could be running lean, disconnect it maybe?
 
frank said:
i think your type opens an air valve andy, that makes it mad lean when you turn the key off.
some types of a/d/v shut the fuel off mechanically eh
Click to expand...
Mine is an air one. There's no chance of it stopping the pump :p plus its connected to the carb... basically thats what is happening I'm introducing lots of air almost stalling it
Enuo said:
When I took mine off my spitfire, all it did was cause run on on low octane fuel so would have to stall engine with the gearbox... I suppose if it s stuck open it could be running lean, disconnect it maybe?
Click to expand...
I can try it. Though it seems to work well allows engine to run and start... and kills engine when asked. Cant hurt to try


I'm thinking about this accelerator pump solenoid... it compensates fuel when sudden air is introduced (quick throttle)... if it has a solenoid it.must operate in different depending on its variables. In my case potentially a water temp sensor and air temp sensor..?.... almost in the crudest way like an 02 sensor. Measuring air temp and coolant/engine and adjusting fuel accordingly
 
SirChris said:
I don't get it

Sent from my Galaxy Nexus using Tapatalk 4
Click to expand...
I reused the old one.... I'm 99% sure it doesnt leak...
I'll put a new one on... heats up... creates a small gap... air leak..

Its lean coz of too much air not lack of fuel. Tested that one yesterday... at least I think so I'll have to go back through it
 
Found yet another unplugged solenoid on the carb. Thus time the wires were cut and couled under the diaphragm at the front
Its the idle-up solenoid.

So 2 solenoids not connected both idle related... joy oh joy
 

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